<template>
  <div class="slide-show" @mouseover="clearInv" @mouseout="runInv">
    <div class="slide-img">
      <a :href="slides[nowIndex].href">
        <transition name="slide-trans">
          <img v-if="isShow" :src="slides[nowIndex].src">
        </transition>
        <transition name="slide-trans-old">
          <img v-if="!isShow" :src="slides[nowIndex].src">
        </transition>
      </a>
    </div>
    <h2>{{ slides[nowIndex].title }}</h2>
    <ul class="slide-pages">
      <li @click="goto(prevIndex)">&lt;</li>
      <li v-for="(item, index) in slides" @click="goto(index)">
        <a :class="{on : index === nowIndex}">{{ index + 1}}</a>
      </li>
      <li @click="goto(nextIndex)">&gt;</li>
    </ul>
  </div>
</template>

<script>
export default {
  props : {
    slides : {
      type : Array,
      default : []
    },
    inv : {
      type : Number,
      default : 4000
    }
  },
  data () {
    return {
      nowIndex : 0,
      isShow : true
    }
  },
  computed : {
    prevIndex () {
      if(this.nowIndex === 0){
        return this.slides.length - 1
      }else{
        return this.nowIndex - 1
      }
    },
    nextIndex () {
      if(this.nowIndex === this.slides.length - 1){
        return 0
      }else{
        return this.nowIndex + 1
      }
    }
  },
  methods : {
    goto (index) {
      this.isShow = false
      setTimeout(() => {
        this.isShow = true
        this.nowIndex = index
        this.$emit('onchange', index)
      }, 10)
    },
    runInv () {
      this.invId = setInterval(() => {
        this.goto(this.nextIndex)
      }, this.inv)
    },
    clearInv () {
      clearInterval(this.invId)
    }
  },
  mounted () {
    this.runInv()
  }
}
</script>

<style scoped>
.slide-trans-enter-active {
  transition: all .5s;
}
.slide-trans-enter {
  transform: translateX(900px);
}
.slide-trans-old-leave-active {
  transition: all .5s;
  transform: translateX(-900px);
}
.slide-show {
  position: relative;
  margin:15px 15px 15px 0;
  width: 900px;
  height: 350px;
  overflow: hidden;
}
.slide-show h2 {
  position: absolute;
  width: 100%;
  height: 100%;
  color: #fff;
  background: #000;
  opacity: 0.5;
  bottom: 0;
  height: 30px;
  line-height: 30px;
  text-align: left;
  padding-left: 15px;
}
.slide-img {
  width: 100%;
}
.slide-img img {
  width: 100%;
  position: absolute;
  top: 0;
}
.slide-pages {
  position: absolute;
  bottom: 0;
  right: 20px;
}
.slide-pages li {
  display: inline-block;
  color: #fff;
  height: 30px;
  margin-right: 20px;
  line-height: 30px;
  text-align: center;
  cursor: pointer;
}
.on {
  color: orangered;
  font-weight: bold;
}
</style>
